Defect-engineered amino-functionalized MIL-100(Fe) for enhanced photocatalytic peroxydisulfate activation and organic pollutant degradation

To improve the performance of MIL-100(Fe) in the photo-peroxydisulfate (photo -PDS) degradation system, this study introduced the amino-containing bidentate ligand 5-aminoisophthalic acid (AIA) to simultaneously engineer structural defects and photosensitive sites, thereby synergistically enhancing both photocatalytic activity and metal-mediated catalytic capability. This study synthesized MIL-100(Fe) materials with varying AIA incorporation levels (denoted as M-x %NH₂) and systematically investigated the effects of AIA integration on the catalyst. Degradation experiments were performed in the photo-PDS system using rhodamine B (RhB) as a model pollutant. The results demonstrate that the introduction of AIA induced multiple advantageous effects in the photo-PDS process:1.It enhanced the visible-light absorption capacity;2.Improved the separation efficiency of photogenerated charge carriers;3.Generated defects to increase metal active sites, thereby accelerating PDS activation. Among the samples, ​M-30 % NH₂ exhibited the optimal performance, achieving nearly complete degradation of RhB within 50 min. The pseudo-first-order rate constant (k) was three times higher than that of unmodified MIL-100(Fe). The catalyst retained approximately 90 % degradation efficiency after five consecutive cycles and demonstrated robust performance across pH 3–9, along with the capability to degrade diverse organic pollutants. Quenching experiments confirmed sulfate radicals (·SO 4 ⁻) and hydroxyl radicals (·OH) as the main active species, and the degradation pathways were elucidated. This study provides foundational insights for modifying MIL-100(Fe) and developing high-efficiency PDS catalysts.